Asthma

This section presents data and statistics on asthma deaths, hospitalisations and prevalence in New Zealand children. You can download factsheets from the Downloads box.

Second-hand smoke exposure [1], nitrogen dioxide exposure [2,3] and indoor dampness and mould [4] can all cause and/or worsen asthma in children.  Outdoor air pollution is also linked to asthma exacerbation [5].

New Zealand has high asthma rates compared with other countries [68]. 

Each year, a small number of children die from asthma

A small number of children die from asthma each year in New Zealand. In 2016, five children died from asthma (Figure 1).

Figure 1:  Annual number of asthma deaths, children aged 0–14 years, 2001–2016

Over 7,000 hospitalisations for childhood asthma in 2018

In 2018, there were 7,182 hospitalisations for asthma (including wheeze) among children aged 0–14 years.

The age-standardised rate for asthma hospitalisations increased from 2002 (473 per 100,000) to 2018 (779 per 100,000) (Figure 2). 

Figure 2: Asthma hospitalisations in children aged 0–14 years, by sex, 2001-2018 (age-standardised rate per 100,000)

Younger children had higher asthma hospitalisation rates

In 2018, children aged 0–4 years had a much higher asthma hospitalisation rate (1,652 per 100,000) than children aged 5–9 years (487 per 100,000) or 10–14 years (176 per 100,000). 

Figure 3: Asthma hospitalisation rates, children aged 0–14 years, by age group and sex, 2018 (crude rate per 100,000)

Pacific children have the highest asthma hospitalisation rates

In 2018, the asthma hospitalisation rate was the highest in Pacific children compared with Māori, Asian and European/Other children, after controlling for age (Figure 4). 

Figure 4: Asthma hospitalisation rates, children aged 0–14 years, by prioritised ethnic group, 2018 (age-standardised rate per 100,000)

In 2018, the asthma hospitalisation rate was higher for children living in the most deprived areas (NZDep 2013 quintile 5) (1,181 per 100,000) than those in the least deprived areas (quintile 1) (588 per 100,000), after adjusting for age. (Figure 5).

Figure 5: Asthma hospitalisation rates, children aged 0–14 years, by NZDep 2013 quintiles, 2018 (age-standardised rate per 100,000)

Highest rates of asthma hospitalisation in Auckland, Lakes, Taranaki and Hutt Valley DHBs

In 2018, there were substantial regional differences in children’s asthma hospitalisation rates. The following DHBs had the highest rates of asthma hospitalisation for children compared to the national rate (Figure 6):
• Auckland (1,268 per 100,000)
• Hutt Valley (1,121 per 100.000)
• Lakes (1,081 per 100,000)
• Hawke’s Bay (1,080 per 100,000)


The lowest asthma hospitalisation rates were in:
• South Canterbury (320 per 100,000)
• MidCentral (473 per 100,000)
• Tairāwhiti (475 per 100,000)

Figure 6: Asthma hospitalisation rates, children aged 0–14 years, by District Health Board, 2018 (age-standardised rate per 100,000)

The percentage of children with medicated asthma over the last ten years has been relatively consistent, adjusting for age differences.

Figure 7: Medicated asthma, children aged 2-14 years, 2006/07-2017/18 (unadjusted prevalence)

Boys were more likely to have medicated asthma than girls

In 2017/18, boys had a much higher rate of medicated asthma (17.3%) than girls (12.3%).

The percentage of children taking asthma medication was somewhat higher for children aged 5-9 years (16.0%) and 10-14 (15.8%) (Figure 6). 

Figure 8: Medicated asthma, children aged 2-14 years, by sex and age group, 2017/18 (unadjusted prevalence)

Fig 6: Medicated asthma, children aged 2-14 years, by sex and age group, 2017/18 (unadjusted prevalence)

Higher rates of medicated asthma among Maori children and in more deprived areas

In 2017/18, the highest rate of medicated asthma was among Māori children (22.9%), followed by Pacific children (16.4%) and European/Other children (14.5%).  Adjusting for age and sex differences, Māori children were 1.9 times more likely than non-Māori children to have medicated asthma.

Children living in the most deprived areas (NZDep2013 quintile 5) had a much higher rate of medicated asthma (19.0%) than children in the least deprived areas (12.5%) (Figure 7).

Figure 9: Medicated asthma, children aged 2–14 years, by neighbourhood deprivation (NZDep2013 quintiles), 2017/18 (unadjusted prevalence)


Fig 7: Medicated asthma, children aged 2-14 years, by NZDep, 2017/18 (unadjusted prevalence)

Highest rates of medicated asthma in Whanganui, MidCentral and Hutt Valley DHBs in 2014-17

In 2014–17, Whanganui DHB (24.4%), MidCentral DHB (21.9%) and Hutt Valley DHB (20.5%) had the highest rates of medicated asthma compared to the national rate (Figure 8).

Figure 10Prevalence of medicated asthma, children aged 2–14 years, by District Health Board, 2014–17 (unadjusted prevalence) 


Fig 8: Medicated asthma, children aged 2-14 years, by DHB, 2014-17 (unadjusted prevalence)

See the factsheet for more details (in the Downloads box).

Information about the data

Asthma hospitalisations

Source: National Minimum Dataset, Ministry of Health

Definition: Acute and semi-acute hospitalisations with asthma (ICD-10AM J45–J46) or wheeze (R06.2) as the primary diagnosis, for children aged 0–14 years. Analyses excluded overseas visitors, deaths, and transfers within and between hospitals. Age-standardised rates per 100,000 people have been presented. 

Asthma prevalence

Source: New Zealand Health Survey, Ministry of Health

Definition: Children aged 2–14 years who have been diagnosed by a doctor as having asthma, and who currently take medication (inhalers, medicine, tablets, pills or other medication) for it. 

For more information about these indicators, see the metadata sheets (in the Downloads box).  

References

1. U.S. Department of Health and Human Services. 2007. Children and Secondhand Smoke Exposure. Excerpts from The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.

2. Belanger K, Holford TR, Gent JF, Hill ME, Kezik JM, Leaderer BP. 2013. Household levels of nitrogen dioxide and pediatric asthma severity. Epidemiology 24(2): 320–330. 

3. Pilotto LS, Nitschke M, Smith BJ, Ruffin RE, McElroy HJ, Martin J, Hiller JE. 2004. Randomized controlled trial of unflued gas heater replacement on respiratory health of asthmatic schoolchildren. Int J Epidemiol. 33(1): 208–214. 

4. Jaakkola MS, Haverinen-Shaughnessy U, Douwes J, Nevalainen A. 2011. Indoor dampness and mould problems in homes and asthma onset in children. In M. Braubach, D.E. Jacobs & D. Ormandy (Eds.), Environmental burden of disease associated with inadequate housing: A method guide to the quantification of health effects of selected housing risks in the WHO European Region (pp. 5–31). Copenhagen: World Health Organization Regional Office for Europe. 

5. Orellano P, Quaranta N, Reynoso J, Balbi B, Vasquez J. 2017. Effect of outdoor air pollution on asthma exacerbations in children and adults: Systematic review and multilevel meta-analysis. PLoS ONE 12(3): e0174050.

6. Prezant B, Douwes J. 2011. Calculating the burden of disease attributable to indoor dampness in New Zealand: Technical Report. Wellington: Centre for Public Health Research.

7. Lai CKW, Beasley R, Crane J, Foliaki S, Shah J, Weiland S. 2009. Global variation in the prevalence and severity of asthma symptoms: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC). Thorax 64: 476–483. 

8. OECD. 2015. CO1.6: Disease-based indicators: prevalence of diabetes and asthma among children. OECD Family Database. Available online: https://www.oecd.org/els/family/CO_1_6_Diabetes_Asthma_Children.pdf  (accessed 30/10/2017).

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